The present invention relates to roadway maintenance and crack repair, and more particularly to systems for cleaning and filling such cracks that typically develop over time in roadways having coatings of concrete or asphalt including bitumen and aggregate and the like.
In roadway maintenance, crack repair traditionally involves manually cleaning the cracks by removing material therefrom, and filling with a material that may contain aggregate. In some cases, a stream of the thermoplastic material is manually directed onto the roadway generally into the crack, with some of the thermoplastic material (such as tar) remaining on the roadway surface on opposite sides of the crack. In other cases, a crack sealant is used to fill cracks that are first enlarged by sawing or routing during the cleaning. U.S. Pat. No. 5,215,071 to Mertes et al. discloses a riding pavement saw having a hydraulically powered blade that rotates on a generally horizontal axis, the blade being supported approximately midway between a pair of front wheels, the machine being steered by a single rear wheel that is operator-controlled.
U.S. Pat. No. 4,407,605 to Wirtgen discloses a powered vehicle having a pavement heater and milling device, modified to provide a rotating chisel cutter for removing a relatively wide portion of the pavement to an adjustable depth in the repair of longitudinal cracks. The milling device is mounted for laterally adjustable positioning relative to the vehicle, whereby initial positioning of the vehicle can be simply parallel to the crack, the vehicle being further maneuvered to follow the crack after the lateral positioning of the milling device is completed. The cutter rotates on a transverse horizontal axis, with chisel elements being spaced along the axis and located within a container that is fed with aggregates and/or liquid to be mixed with pavement that is removed by the milling device, the augmented aggregate mix being reapplied from the container onto the roadway.
U.S. Pat. No. 4,954,010 to Montgomery et al. discloses a maintenance truck equipped with a transverse-mounted slurry sealant box assembly for filling transverse roadway cracks and blending stepped pavement segments
These and other devices for roadway crack cleaning and repair have a number of disadvantages including, for example, one or more of the following:
1. They are excessively large and consequently difficult to maneuver, in many cases also requiring excessive lane width to be closed to regular traffic; PA1 2. They are difficult to use in that the operator is required to manually steer the vehicle to accurately follow the crack, being particularly difficult when the driver's position does not afford a clear view of the crack and/or when lighting conditions are poor; PA1 3. They have limited capability for following random cracks in that the cutters rotate on horizontal or generally horizontal axes; PA1 4. They have limited effectiveness in that optional secondary operations that are indicated for portions of certain cracks (based on visual inspection, for example) are not permitted prior to filling; and PA1 (a) providing a crack cleaning module including a steerable first vehicle for navigating the roadway and having a first platform assembly laterally movable relative to the first vehicle in response to a first control signal, a first sensor unit being mounted on the first platform for detecting local variations in a sensed parameter during movement of the first vehicle, a sensed continuous local deviation of the parameter being indicative of the roadway crack; a first controller responsive to the first sensor unit for generating the first control signal, the control signal reflecting a sensed lateral position of the crack relative to the first sensor; a first actuator for laterally moving the first platform assembly in response to the first control signal; and a router unit mounted on the first platform behind the sensor unit and laterally aligned therewith; PA1 (b) providing a crack sealing module including a steerable second vehicle for navigating the roadway and having a second platform assembly laterally movable relative to the second vehicle in response to a second control signal, a second sensor unit being mounted on the second platform for detecting local variations in a sensed parameter during movement of the second vehicle, a sensed continuous local deviation of the parameter being indicative of the roadway crack; a second controller responsive to the second sensor unit for generating the second control signal, the control signal reflecting a sensed lateral position of the crack relative to the second sensor; a second actuator for laterally moving the second platform assembly in response to the second control signal; and a sealer outlet mounted on the second platform behind the sensor unit and laterally aligned therewith; PA1 (c) driving the first vehicle to generally follow the crack; PA1 (d) activating the first controller for driving the first actuator thereby to track the crack; PA1 (e) activating the router unit for machining opposite sides of the crack as the first platform is positioned for more closely following the crack in response to the first sensor unit; PA1 (f) removing loosened material from the crack and from the roadway proximate the crack; PA1 (g) driving the second vehicle to generally follow the crack after the machining by the router unit; PA1 (h) activating the second controller for driving the second actuator thereby to track the crack; and PA1 (i) feeding a sealant medium through the sealer outlet as the second platform is positioned for more closely following the crack in response to the second sensor unit, at least a portion of the sealant medium flowing into the crack, thereby repairing the crack. PA1 (a) providing a scarifier appliance on the first platform ahead of the first sensor unit for loosening foreign material on the roadway proximate the crack; and PA1 (b) vacuuming loosened material from the roadway between the scarifier appliance and the first sensor unit. PA1 (a) providing a pressure roller on the second platform behind the sealer outlet for compacting the sealant medium and the roadway proximate the crack; PA1 (b) feeding a particulate material onto the roadway between the sealer outlet and the pressure roller for preventing adhesion of sealant medium onto the pressure roller; and PA1 (c) compacting portions of the particulate material into the sealant within the crack by the pressure roller. PA1 (a) activating a bias input of one of the controllers for selecting one branch of the branched segment to be followed by a corresponding one of the sensor units; and PA1 (b) biasing the control signal for driving the platform toward the one branch in response to the bias input when the one sensor unit detects a laterally spaced pair of continuous local deviations of the sensed parameter.
5. They are expensive to provide and operate in that they require heating and/or removal of excessive amounts of roadway material.
Thus there is a need for a roadway crack cleaning and repair system that overcomes the disadvantages of the prior art.